{ ack(0,0) = 1 ack(0,1) = 2 ack(0,2) = 3 ack(0,3) = 4 ack(0,4) = 5 ack(0,5) = 6 ack(1,0) = 2 ack(1,1) = 3 ack(1,2) = 4 ack(1,3) = 5 ack(1,4) = 6 ack(1,5) = 7 ack(2,0) = 3 ack(2,1) = 5 ack(2,2) = 7 ack(2,3) = 9 ack(2,4) = 11 ack(2,5) = 13 ack(3,0) = 5 ack(3,1) = 13 ack(3,2) = 29 ack(3,3) = 61 ack(3,4) = 125 ack(3,5) = 253 } #19 / [2]